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Severe immune response kills SARS victims
NewScientist.com news service ^ | May 3, 2003 | Robert Walgate

Posted on 05/02/2003 8:39:46 AM PDT by CathyRyan

An excessive immune reaction appears to be the fatal factor in patients who die of SARS, according to medical data from Hong Kong. The best estimate of the fatality rate of SARS is rising steadily and so understanding how the disease causes death is critical to finding the best treatments.

Scientists have also discovered that the SARS virus can remain viable for at least 24 hours after being deposited in a droplet on a plastic surface - a simulation, for example, of an infected person coughing on to the wall of a lift.

The new information was revealed by Klaus Stöhr, the World Health Organization's chief scientist for SARS in a briefing earlier this week. "In the first week or so of disease the virus is replicating mainly in the upper respiratory tract, causing high fever and dry cough. But in the second week we see an over-reaction of the immune response, and in 20 per cent of cases that leads to very severe disease."

Mark Salter, WHO's coordinator for the clinical management of SARS, told New Scientist that this excessive response seems to be destroying the alveoli, the tiny sacs at the end of the lung tubing where the oxygen is absorbed. It is like stripping all the leaves from a tree, he says, making breathing extremely difficult.

"The immune response develops, but then continues growing unchecked" says Salter. "You then get cytokines, tumour necrosis factor and so on released not just at the virally infected cells they are supposed to kill, but throughout the tissue". This also happens in other diseases but the mechanism is not entirely understood, and certainly not in the case of SARS, he says.

Flare up

Nevertheless the observation significantly strengthens the basis on which doctors can select the treatments given to patients. In particular, it suggests the use of corticosteroids, alongside other drugs that reduce the viral load such as interferon.

Corticosteroids suppress the immune system and are normally used against asthma, rheumatoid arthritis and in transplant patients to reduce the risk of rejection.

Their use does raise the risk of further infection, but Hong Kong hospitals are claiming success with combinations of the antiviral ribavirin and pulsed steroids, says Salter: "And once steroids are stopped, they see a flare up of the condition suggesting there is a significant immune component to the disease."

. The issue of how long the virus survives outside the body was also raised by Stöhr. Some scientists have argued that long survival could explain unusual cases of transmission in Hong Kong and Canada.

In a study in Germany reported by Stöhr, the virus was dropped in liquid on to a plastic surface, the drop was dried, and examined after 24 hours. "There were 10,000 virus units per millitre before, and after 24 hours there were 1000 - and that was viable viruses."


TOPICS: News/Current Events
KEYWORDS: ards; autoimmune; death; fatalfactor; fipv; flareup; nopanic; sars; virussurvives
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1 posted on 05/02/2003 8:39:46 AM PDT by CathyRyan
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To: CathyRyan
Good news for AIDS patients, I guess. :-P
2 posted on 05/02/2003 8:41:56 AM PDT by Sloth ("I feel like I'm taking crazy pills!" -- Jacobim Mugatu, 'Zoolander')
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To: aristeides
ping
3 posted on 05/02/2003 8:52:00 AM PDT by Thud
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To: CathyRyan; Mother Abigail; Dog Gone; Petronski; per loin; riri; flutters; Judith Anne; ...
This would be consistent with what Laurie Garrett was saying about receptors.
4 posted on 05/02/2003 8:57:18 AM PDT by aristeides
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To: Thud
Thanks for the ping.
5 posted on 05/02/2003 8:57:58 AM PDT by aristeides
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To: CathyRyan
If I catch this, I want them to treat me with enough steroids to turn me into Arnold Schwarzenegger.
6 posted on 05/02/2003 9:16:28 AM PDT by Dog Gone
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To: Dog Gone
You are talking about anabolic, they are talking about corticosteriods, in particular cortisol. Different stuff.
7 posted on 05/02/2003 11:12:54 AM PDT by Iris7 (Sufficient for evil to triumph is for good people to be imprudent.)
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To: CathyRyan; Mother Abigail; Dog Gone; Petronski; per loin; riri; flutters; Judith Anne; ...
Prospective study of the clinical progression and viral load of SARS associated coronavirus pneumonia in a community outbreak

JSM Peiris, CM Chu, VCC Cheng, KS Chan, IFN Hung, LLM Poon, KI Law, BSF Tang, TYW Hon, CS Chan, KH Chan, JSC Ng, BJ Zheng, WL Ng, RWM Lai, Y Guan, KY Yuen and members of the HKU / UCH SARS Study Group

This paper has been accepted by The Lancet and will be published next week. We are grateful to The Lancet for the permission to publish the summary of this paper in advance.

Summary

Background:

A community outbreak of severe acute respiratory distress syndrome (SARS) with epidemiological linkage was reported. The temporal progression of the clinical, radiological, and virological changes was investigated.

Methods:

A prospective study of the clinical, haematological, radiological, and microbiological findings of 75 patients managed with a standardized treatment protocol of the Hospital Authority, Hong Kong Special Administrative Region using ribavirin and corticosteroid was performed over a 3 week period. The pattern of clinical disease, viral load, the risk factors for a poor clinical outcome and the usefulness of virological diagnostic methods was presented and analyzed.

Findings:

The fever and pneumonia initially responded to treatment. However, patients developed recurrent fever (85.3%) on day 8.9 ± 3.1 (range 4 to 18), watery diarrhoea (73.3%) on day 7.5 ± 2.3 (range 3 to 15), radiological deterioration (80%) on day 7.4 ± 2.2 (range 3 to 13) and respiratory deterioration (45.3%) on day 8.6 ± 3 days (range 5 to 19). In 45.3% of patients, marked improvement of initial pulmonary lesions was closely associated with appearance of new radiological lesions at other sites. Twenty percent progressed to acute respiratory distress syndrome (ARDS) during the third week. Quantitative RT-PCR of nasopharyngeal aspirates in 14 patients (4 had ARDS and 10 without ARDS) consistently demonstrated a peak viral load at day 10 and a decrease to admission level at day 15. Age and chronic HBV infection are independent significant risk factors for progression to ARDS on multivariate analysis. Faecal excretion of coronavirus was present and continued through the period of follow-up. Seroconversion and RT-PCR of nasopharyngeal aspirates and stool are useful for confirmation of SARS.

Interpretation:

The consistent clinical progression, shifting radiological infiltrates and an inverted V viral load profile suggested that deterioration during the second week is not related to uncontrolled viral replication but may rather be related to immunopathological damage. Age and HBV status are risk factors for progression to ARDS.

http://www.who.int/csr/sars/prospectivestudy/en/index.html

8 posted on 05/02/2003 11:20:10 AM PDT by aristeides
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To: aristeides
Thank you, good find. :)

The topic of sars seems to be slowing. I wonder if people are getting burnt out on it?
9 posted on 05/02/2003 11:26:42 AM PDT by CathyRyan
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To: aristeides; CathyRyan; Judith Anne; Dog Gone; riri; blam
Lots and lots of SARS articles in todays,May 2,Wall Street Journal.

The whole SARS mess gets bigger and bigger.

No accurate testing.

No good accurate diagnostic definition.

No good tratment.

No vaccine.

Continual new cases.

Continual new deaths.

Continual loss to the worlds economies.

Clearly the biggest story in the world.

Cant wait to hear Presidential candidates on this.

10 posted on 05/02/2003 11:41:02 AM PDT by Betty Jo
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To: Iris7
Well, darn.
11 posted on 05/02/2003 12:06:52 PM PDT by Dog Gone
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To: Betty Jo
It maybe the biggest story in the world but is looks like it is starting to run out of steam on FR.
12 posted on 05/02/2003 12:20:25 PM PDT by CathyRyan
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To: Dog Gone
I want them to treat me with enough Growth Hormone to make my immune system think I am six years old and a ton of cortisteroids (unfortunately catabolic!) and maybe some singulair for the hell of it!
13 posted on 05/02/2003 12:45:52 PM PDT by Nov3
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To: aristeides
Severe immune response kills SARS victims?? Are you saying his own bodies immune system killed him?

I assume your an MD, can you simplify ,and summorize for us peons?
14 posted on 05/02/2003 2:09:50 PM PDT by wiseone
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To: CathyRyan; Domestic Church
Unfortunately, I don't think we are fortunate enough to just "burn out" on this story. We are stuck with it.

DC, maybe you can anser this..I have a nagging question. Why is this virus so durable? Are other corona viruses this durable and capable of living for such long periods of time?

Admitted tin foil time, but is the durability something that could have been "added"? Could someone have taken the durability of a, say, smallpox virus and somehow given it to a virus such as this?

15 posted on 05/02/2003 2:11:29 PM PDT by riri
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To: wiseone
I'm not an M.D. (I'm a lawyer,) so I don't trust myself to summarize these articles accurately. But my understanding of them is the same as yours.
16 posted on 05/02/2003 2:16:53 PM PDT by aristeides
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To: riri; vetvetdoug
The coronavirus that causes feline infectious peritonitis (FIP) can survive on surfaces for weeks.
17 posted on 05/02/2003 2:22:24 PM PDT by aristeides
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To: aristeides
Yikes. I wonder how long this virus truly can survive outside a host?!

I bought the big industrial sized Purell today. When the cashier went to put it on the bag, I said "Thanks, can I have that, I am going to carry it in my purse" She looked at me like, "Okaaaay"

18 posted on 05/02/2003 2:42:17 PM PDT by riri
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To: CathyRyan
"It maybe the biggest story in the world but is looks like it is starting to run out of steam on FR."

Nah. Most of us just can't think of any thing else to say, at least I can't.

19 posted on 05/02/2003 2:55:21 PM PDT by blam
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To: blam
I can not either. Guess that is why I just cut and paste.
20 posted on 05/02/2003 2:58:25 PM PDT by CathyRyan
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